<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>导航栏</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        ul{
            width: 300px;
            list-style-type: none;
        }
        li a{
            display: block;
            background-color: rgb(175, 174, 174);
            text-decoration: none;
            color: white;
            font-size: 16px; font-weight: 700;
            border: violet 1px solid;
        }
    </style>
</head>
<body>
    <ul>
        <li><a href="#">A</a></li>
        <li><a href="#">A</a></li>
        <li><a href="#">A</a></li>
        <li><a href="#">A</a></li>
        <li><a href="#">A</a></li>
    </ul>
</body>
</html>